Clairvoyance means literally nothing more than “clear seeing”, and it is a word which has been sorely misused, and even degraded so far as to be employed to describe the trickery of a mountebank in a variety show. Even in its more restricted sense it covers a wide range of phenomena, differing so greatly in character that it is not easy to give a definition of the word which shall be at once succinct and accurate.
For the purpose of this treatise we may, perhaps, define it as the power to see what is hidden from ordinary physical sight. It will be as well to premise that it is very frequently (though by no means always) accompanied by what is called clairaudience, or the power to hear what would be inaudible to the ordinary physical ear.
Students often ask how this clairvoyant faculty will first be manifested in themselves—how they may know when they have reached the stage at which its first faint foreshadowings are beginning to be visible. Cases differ so widely that it is impossible to give to this question any answer that will be universally applicable.
Some people begin by a plunge, as it were, and under some unusual stimulus become able just for once to see some striving vision; and very often in such a case, because the experience does not repeat itself, the seer comes in time to believe that on that occasion he must have been the victim of hallucination.
Others begin by becoming intermittently conscious of the brilliant colours and vibrations of the human aura; yet others find themselves with increasing frequency seeing and hearing something to which those around them are blind and deaf; others, again, see faces, landscapes, or coloured clouds floating before their eyes in the dark before they sink to rest; while perhaps the commonest experience of all is that of those who begin to recollect with greater and greater clearness what they have seen and heard on the other planes during sleep.
[Let’s] consider the various phenomena of clairvoyance:
They differ so widely both in character and in degree that it is not very easy to decide how they can most satisfactorily be classified.
1.. We might, for example, arrange them according to the kind of sight employed – whether it were mental, astral, or merely etheric.
2.. We might divine them according to the capacity of the clairvoyant, taking into consideration whether he was trained or untrained; whether his vision was regular and under his command, or spasmodic and independent of his volition; whether he could exercise it only when under mesmeric influence, or whether that assistance was unnecessary for him; whether he was able to use his faculty when awake in the physical body, or whether it was available only when he was temporarily away from that body in sleep or trance.
All these distinctions are of importance, and we shall have to take them all into consideration as we go on, but perhaps on the whole the most useful classification will be one something on the lines of that adopted by Mr. Sinnett in his Rational of Mesmerism—a book, by the way, which all students of clairvoyance ought to read.
In dealing with the phenomena, then, we will arrange them rather according to the capacity of the sight employed than to the plane upon which it is exercised, so that we may group instances of clairvoyance under some such headings as these:
1.. Simple clairvoyance—that is to say, a mere opening of sight, enabling its possessor to see whatever astral or etheric entities happen to be present around him, but not including the power of observing either distance places or scenes belonging to any other time than the present.
2.. Clairvoyance in space—the capacity to see scenes or events removed from the seer in space, and either too far distant for ordinary observation or concealed by intermediate objects.
3.. Clairvoyance in time—that is to say, the capacity to see objects or events which are removed from the seer in time, or, in other words, the power of looking into the past or the future.
— excerpt from Clairvoyance, by C.W. Leadbeater,